The invention provides a star-block, polyethylene glycol based polymeric material having a uniform distribution of both hydroxy and amine functional groups throughout the resin. The invention also provides methods for making and using the star-blocked polymeric material.
Solid supports are increasingly used in organic synthesis, spectroscopic analysis, solid phase screening, chromatographic separations, and enzymatic assays. Suitable solid supports are typically polymeric resins that are chemically inert under a wide range of reaction conditions, mechanically stable, and compatible with a variety of solvents with differing polarity. No single resin has been developed that is compatible with all types of reactions or with all types of applications.
Solid supports are particularly useful with combinatorial or orthogonal chemistry for synthesizing large libraries of organic compounds. For example, large libraries of compounds that can be evaluated as new drugs can be prepared using solid supports with combinatorial or orthogonal chemistry. Solid supports simplify product isolation and allow the use of excess reagents to force reactions to completion.
The most common solid supports for solid-phase organic synthesis are spherical resin beads of either highly cross-linked gel type polystyrene polymers containing about 1 to 2 weight percent divinylbenzene or polyethylene glycol (PEG) grafted polystyrene copolymers. The polystyrene resins do not swell in polar protic solvents such as alcohols and water. Accessibility to all reaction sites can be compromised. The PEG grafted resins such as TentaGel(trademark) (Rapp Polymere GmbH; Txc3xcbingen, Germany) and ArgoGel(trademark) (Argonault Technologies; San Carlos, Calif.) tend to have relatively uniform swelling in a variety of solvents ranging from toluene to water. However, these resins have limited use with enzymatic reactions.
Other PEG-based solid supports have been developed. For example, poly(ethylene glycol)-poly(acrylamide) (PEGA) was the first resin compatible with both aqueous solutions and enzymatic reactions. The family of PEG-based resins has been extended to include polyoxyethylene-polyoxypropylene (POEPOP), polyoxyethylene-polyoxetane (SPOCC), and polyoxyethylene-polystyrene (POEPS-3) resins that have similar compatibility with aqueous enzymatic chemistry.
PEG-based resins have been used in on-bead assays for the determination of inhibitors of proteolytic enzymes, where two different compounds (the substrate and the inhibitor) on a single bead compete for the enzyme (the one-bead-two-compounds concept). To attach two compounds to one bead, bifunctional resins are needed. Previously, bifunctionality has been accomplished by derivatisation of a monofunctional resin with a mixture of two different linkers or by using an orthogonal protecting strategy on Nxcex1 and Nxcex5 of lysine. Bifunctional resins are commercially available such as bifunctional TentaGel(trademark) but the bifunctionality is not evenly distributed throughout the bead.
The invention relates to a polyethylene glycol (PEG) based polymeric material having a uniform distribution of both hydroxy and amine functional groups throughout the resin. The polymeric materials, known as HYDRA resins, are prepared by initially forming a polyimine compound through reaction of an aldehyde and an amine. The polyimine is further reacted with a reducing agent to form a star-blocked polymeric material with two types of functional groups.
In one embodiment of the invention, the aldehyde is prepared by partially oxidizing the hydroxy end groups of a polyethylene glycol. The amine is a branched compound having three or more primary amine groups. The aldehyde and amine groups react to form a polyimine. The polyimine is reduced to form a HYDRA resin containing PEG chains cross-linked with a branched amine.
In another embodiment of the invention, the aldehyde is a compound containing three to six aldehyde groups and functioning as a cross-linker. The aldehyde is reacted with a PEG having two amine end groups. The aldehyde and amine groups react to form a polyimine that is subsequently reduced to form a HYDRA resin.
The bifunctional HYDRA resin can be used in a broad range of solvents and under a variety of chemical reaction conditions. The resins can be permeated by large biomolecules such as enzymes. The difference in reactivity between the hydroxy and amine groups allows the HYDRA resin to be used as a solid support for combinatorial chemistry, chromatographic separations, immobilization of biomolecules, and controlled release of drugs. The polymeric material can be used in a polymeric coating or film, in an implant, or as an adsorbent.